我想为文本字段提供一个初始值,并重新绘制一个空值以清除文本。用Flutter的api实现这一点的最佳方法是什么?
当前回答
如果你使用TextEditingController只需要在你的类中使用这一行。
TextEditingController txtController = TextEditingController(text: 'Initial value')
TextField(
controller: txtController,
);
如果你不使用TextEditingController就去initialValue
TextFormField(
initialValue: 'your initial text',
);
完整代码
class _TestScreen extends State<Test> {
TextEditingController _controller;
@override
void initState() {
super.initState();
_controller = new TextEditingController(text: 'Initial value');
}
@override
Widget build(BuildContext context) {
return new Column(
children: <Widget>[
TextField( // First method
initialValue: "Initial text"
),
TextField( // Second method
controller: _controller, // Controller has the initial value
),
],
);
}
}
其他回答
内部类,
final usernameController = TextEditingController(text: 'bhanuka');
文本框,
child: new TextField(
controller: usernameController,
...
)
(来自邮件列表。这个答案不是我想出来的。)
class _FooState extends State<Foo> {
TextEditingController _controller;
@override
void initState() {
super.initState();
_controller = new TextEditingController(text: 'Initial value');
}
@override
Widget build(BuildContext context) {
return new Column(
children: <Widget>[
new TextField(
// The TextField is first built, the controller has some initial text,
// which the TextField shows. As the user edits, the text property of
// the controller is updated.
controller: _controller,
),
new RaisedButton(
onPressed: () {
// You can also use the controller to manipuate what is shown in the
// text field. For example, the clear() method removes all the text
// from the text field.
_controller.clear();
},
child: new Text('CLEAR'),
),
],
);
}
}
如果你使用TextEditingController只需要在你的类中使用这一行。
TextEditingController txtController = TextEditingController(text: 'Initial value')
TextField(
controller: txtController,
);
如果你不使用TextEditingController就去initialValue
TextFormField(
initialValue: 'your initial text',
);
完整代码
class _TestScreen extends State<Test> {
TextEditingController _controller;
@override
void initState() {
super.initState();
_controller = new TextEditingController(text: 'Initial value');
}
@override
Widget build(BuildContext context) {
return new Column(
children: <Widget>[
TextField( // First method
initialValue: "Initial text"
),
TextField( // Second method
controller: _controller, // Controller has the initial value
),
],
);
}
}
你可以做以上所有的事情,但如果你想让API在加载时显示你的数据,它会像配置文件页面一样显示。下面是代码:
TextEditingController _nameController = TextEditingController(); // initialize the controller
// when API gets the data, do this:
_nameController.text = response.data.fullName; or _nameController.text = "Apoorv Pandey"
我希望这能澄清一切。编码快乐!
class _YourClassState extends State<YourClass> {
TextEditingController _controller = TextEditingController();
@override
void initState() {
super.initState();
_controller.text = 'Your message';
}
@override
Widget build(BuildContext context) {
return Container(
color: Colors.white,
child: TextFormField(
controller: _controller,
decoration: InputDecoration(labelText: 'Send message...'),
),
);
}
}